1. Field of the Invention
The present invention relates to a lighting control apparatus (for controlling a light such as a turn signal light, headlights, etc.) for an automatic following travel system wherein a leading vehicle is operated by an operator, and vehicles automatically follow the leading vehicle (hereinafter referred to as xe2x80x9cfollowing vehiclesxe2x80x9d).
This application is based on Japanese Patent Application Nos. 11-00651, and 11-103392, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Recently, automatic following travel systems have been proposed wherein a leading vehicle is operated by an operator, and following vehicles automatically follow the leading vehicle. These automatic following travel systems reduce labor required to drive the second and succeeding vehicles.
In the conventional automatic following travel system, a driver manually turns on or off turning signal lights by himself to turn right or left at a crossing, or to change traffic lanes.
The conventional automatic following travel system, however, has the following problems.
When turning right or left or changing traffic lanes while one or more vehicles automatically follow a single leading vehicle in such a manner as to form a line, the driver in the leading vehicle turns on the turn signal lights, and the turn signal lights flashes on and off, but the turn signal lights of the unmanned following vehicles are not turned on.
Therefore, pedestrians or drivers in oncoming vehicles cannot know the behavior of the entire line and of the respective individual following vehicles. Further, a driver in a vehicle behind the line cannot anticipate that the last vehicle in the line may start turning right or left or changing traffic lanes.
When it becomes dark, positioning lights for making other persons aware of the positions of the vehicles themselves, and headlights that cast light on the road ahead of the vehicles must be turned on. The operations for turning on or off the positioning lights and the headlights are manually carried out by the driver.
This may be true when turning on or off other lights such as hazard lights for making following vehicles aware of the vehicles stopped due to an emergency, or stop lights for making the following vehicles aware of the braking of the leading vehicle.
The lighting control device of the conventional automatic following travel system has the following problem.
When the vehicles travel in line at night, a driver in the leading vehicle must go to all the following vehicles to turn on the headlights. In particular, this is a burden on the driver when there are a number of the following vehicles. Further, it takes much time to prepare for the travel in line before the starting of the vehicles.
Since the following vehicles are automatically driven in an unmanned manner, the headlights need not be lighted to cast light on the road even at night. However, while the headlights are not lighted, pedestrians or drivers in oncoming vehicles may miss the following vehicles when the vehicles traveling in line turn at a crossing. To avoid this, the headlights of the following vehicles should be always lighted when the vehicles travel in line.
When the vehicles travel close to each other while maintaining a short distances from each other, the respective following vehicles travel after their preceding vehicles normally at the interval of three or four meters, and the headlights simply throw light on the rear of the respective preceding vehicles and do not make pedestrians, etc., aware of the vehicles. That is, it wastes energy to always light the headlights to ensure the visibility when the vehicles turn a crossing, and this waste of energy is serious for the vehicle of the automatic following travel system which uses batteries as the driving sources.
It is therefore an object of the present invention to provide a lighting control system for an automatic following travel system which can turn on or off a light of unmanned following vehicles, corresponding to an on-off action of a light of manned leading vehicle, when the vehicles are traveling in line.
It is therefore another object of the present invention to provide a lighting control system for an automatic following travel system which can appropriately change a timing for turning on the lighting device of the following vehicle or can turn off the light if necessary, and can lengthen the life of the light.
In a first aspect of the present invention, in the lighting control apparatus of present invention for an automatic following travel system in which a leading vehicle (1, 101) is operated by an operator, and at least one following vehicle (2, 102) automatically follows the leading vehicle, the leading vehicle comprises a light operating device (e.g., a turn signal switch 12, or a lighting switch 112) for turning on or off a light (such as turn signal lights, headlights, positioning lights, hazard lights, and stop lights) of the leading vehicle, and a transmitter (radio communicator 20, or 120) for transmitting information indicating the operation of the light operating device, and the following vehicle comprises: a receiver (radio communicator 20, or 120) for receiving the information from the transmitter; and a light operating device (turn signal operating device 23, or lighting operating device 123) for producing an operation signal for turning on or off a light of the following vehicle, based on the information received by the receiver.
When a driver in the leading vehicle turns on the light such as the turn signal light, or headlights, the operation information is sent via the transmitter to the following vehicle. Based on the information received by the receiver, the following vehicle produces the operation signal for turning on the light corresponding to the light of the leading vehicle which has been turned on. Thus, corresponding to the operation by the driver in the leading vehicle, the corresponding light is flashed on and off.
Then, when a driver in the leading vehicle turns off the light, the operation information is sent via the transmitter to the following vehicle. Based on the information received by the receiver, the following vehicle produces the operation signal for turning off the light corresponding to the light of the leading vehicle which has been turned off. Thus, corresponding to the operation by the driver in the leading vehicle, the corresponding light is turned off.
In a second aspect of the present invention, the light is a turn signal light, and the light operating device is a turn signal operating device (23).
When a driver in the leading vehicle turns on the turn signal light, the operation information is sent via the transmitter to the following vehicle. Based on the information received by the receiver, the following vehicle produces the operation signal for turning on the light corresponding to the light of the leading vehicle which has been turned on. Thus, corresponding to the turn signal operation by the driver in the leading vehicle, the turn signal light on the same side is flashed on and off.
Then, when a driver in the leading vehicle turns off the turn signal light, the operation information is sent via the transmitter to the following vehicle. Based on the information received by the receiver, the following vehicle produces the operation signal for turning off the light corresponding to the light of the leading vehicle which has been turned off. Thus, corresponding to the turn signal operation by the driver in the leading vehicle, the turn signal light on the same side is turned off.
According to the invention, the turn signal lights of the following vehicles are turned on or off, corresponding to the on-off action of the turn signal light of the leading vehicle. Therefore, pedestrians or drivers in oncoming vehicles can easily see the movement of the entire line of the vehicles and the respective individual following vehicles. Further, a driver in a vehicle behind the line can anticipate the turning to the right or left of the last vehicle of the line in front, and the change in traffic lane.
In a third aspect of the present invention, the turn signal operating device produces an operation signal for turning off the turn signal light, only when receiving via the receiver information indicating that the turn signal light of the leading vehicle has been turned off and when the following vehicle has finished turning and starts driving straight (steps 19 to 21 in the second embodiment).
After the leading vehicle has finished turning at the crossing and has turned off the turn signal light, even when the following vehicles do not enter the crossing or is turning at the crossing, or when the following vehicles are turning at the crossing, the turn signal light is kept on, and is turned off until the following vehicles have finished turning at the crossing. Therefore, a driver in a vehicle behind the line of the vehicles may not receive appropriate indication of the turning of the vehicles.
In a fourth aspect of the invention, the turn signal operating device produces an operation signal for turning on or off the turn signal light, only when receiving via the receiver information indicating that the turn signal light of the leading vehicle has been turned on or off and when the following vehicle reaches the point where the leading vehicle passed at the time of reception of the information (steps 35, 36, 42, and 43 in the third embodiment)
The following vehicle does not turn on or off the turn signal light when simply receiving via the receiver information indicating that the turn signal light of the leading vehicle has been turned on or off. Then, the following vehicle keeps traveling, and reaches the point where the leading vehicle passed at the time of reception of the information, at which point the turn signal light is turned on or off.
Thus, the following vehicle turns on the turn signal light just when the following vehicle enters the crossing, and turns it off just when the following vehicle finishes turning at the crossing. Therefore, just when the leading vehicle leading a long line of the vehicles enters the crossing and turns on the turn signal light, the following vehicles are prevented from turning on the turn signal too early, since they have not entered the crossing and the crossing is distant.
In a fifth aspect of the invention, the transmitter of the leading vehicle transmits position information indicating where the leading vehicle turns on or off the turn signal light, the receiver of the following vehicle receives the position information, and the turn signal operating device produces an operation signal for turning on or off the turn signal light, only when receiving via the receiver information indicating that the turn signal light of the leading vehicle has been turned on or off and when the following vehicle reaches where the leading vehicle turned on or off the turn signal light (steps in the fourth embodiment).
In a manner similar to the fourth aspect of the invention, the following vehicle does not turn on or off the turn signal light when simply receiving via the receiver information indicating that the turn signal light of the leading vehicle has been turned on or off. Then, the following vehicle keeps traveling, and reaches the point where the leading vehicle passed at the time of reception of the information, at which point the turn signal light is turned on or off.
While in the invention of the fourth aspect the following vehicle calculates the point where the leading vehicle has turned on or off the turn signal light, in the invention of the fifth aspect the leading vehicle transmits the information of the position of the leading vehicle together with the turn signal operation information. Therefore, the following vehicle does not have to calculate the point where the leading vehicle has turned on or off the turn signal, thereby simplifying the control process.
In a sixth aspect of the invention, in the lighting control apparatus for an automatic following travel system in which a leading vehicle is operated by an operator, and at least one following vehicle automatically follows the leading vehicle, the following vehicle comprises: a sensor (a laser radar 118 in the sixth embodiment, an angle difference sensor 141 in the seventh embodiment, or other sensors) for calculating information indicating the relationship between the positions of the following vehicle and a vehicle in front which is the leading vehicle or another following vehicle; and a light operating device (a first headlight operating device 133 in the sixth embodiment, a second headlight operating device 142 in the seventh embodiment, or devices for operating other lights) for turning on a light (headlights 131 in the sixth embodiment, turn signal lights, positioning lights, hazard lights, or stop lights) when the value measured by the sensor exceeds a first predetermined value (upper threshold values in the sixth and seventh embodiment) while a light switch (a headlight switch 132 in the sixth embodiment, or switches for operating other lights) has been turned on, and for turning off the light when the value measured by the sensor is equal to or below a second predetermined value (lower threshold values in the sixth and seventh embodiment) even while the light switch has been turned on.
When the vehicles are traveling in line, the lighting control apparatus which can turn on or off the light of unmanned following vehicles, corresponding to the on-off action of the light of manned leading vehicle. The driver in the leading vehicle does not have to go to the respective following vehicles to turn on or off the light, reducing labor of the driver who operates the light. Further, the driver does not have to directly turn on or off the light of the following vehicles, thereby shortening a time required to start travel in line at night, and also shortening a time required to terminate the travel in line.
In a seventh aspect of the present invention, the light in the sixth aspect is a headlight, and the light operating device in the sixth aspect is a headlight operating device (a first headlight operating device 133).
In an eighth aspect of the present invention, the sensor in the seventh aspect is a distance sensor (laser radar 118 in the sixth embodiment) for measuring the distance between the following vehicle and the vehicle in front.
While the lighting switch has been turned on, when the value measured by the distance sensor, that is, the distance between the following vehicle and the leading vehicle exceeds the predetermined value, the headlight operating device turns on the headlights.
Even while the headlight switch has been turned on, when the value measured by the distance sensor is equal to or below the predetermined value, the headlights are turned off.
That is, when the vehicles travel in line, the headlights of the unmanned following vehicles are automatically turned on or off, depending on the distances between the following vehicles and the leading vehicle. Because the headlights are turned on, depending on the circumstances, the batteries are prevented from being wasted.
In a ninth aspect of the present invention, the sensor in the sixth aspect is an angle difference sensor (angle difference sensor 41 in the seventh embodiment) for measuring the difference in angle between the following vehicle and the vehicle in front.
While the lighting switch has been turned on, when the value measured by the angle difference sensor, that is, the difference in angle between the following vehicle and the leading vehicle exceeds the predetermined value, the headlight operating device turns on the headlights.
Even while the headlight switch has been turned on, when the value measured by the angle difference sensor is equal to or below the predetermined value, the headlights are turned off.
That is, when the vehicles travel in line, the headlights of the unmanned following vehicles are automatically turned on or off, depending on the differences in angle between the following vehicles and the leading vehicle. Therefore, the batteries are prevented from being wasted.
In a tenth aspect of the present invention, the sensor in the sixth aspect is a lateral deviation sensor for measuring the lateral deviation between the following vehicle and the vehicle in front.
When the value measured by the lateral deviation sensor, that is, the lateral deviation of the following vehicle with respect to the leading vehicle exceeds the predetermined value, the headlight operating device turns on the headlights. When the lateral deviation is equal to or below the predetermined value, the headlights are turned off.
That is, when the vehicles travel in line, the headlights of the unmanned following vehicles are automatically turned on or off, depending on the lateral deviation of the following vehicles with respect to the leading vehicle. Therefore, the batteries are prevented from being wasted.
In an eleventh aspect of the present invention, in the lighting control apparatus for an automatic following travel system, the following vehicle comprises a determining device (steps 152 and 154 in the eighth embodiment) for determining whether the light is to be turned on or off, based on information concerning the condition of the leading vehicle transmitted via inter-vehicle communication. When the determining device determines that the light is to be turned on while a light switch has been turned on, the light is turned on. When the determining device determines that the light is to be turned off even while the light switch has been turned on, the light is turned off.
In this invention of the eleventh aspect, the determining device of the following vehicle determines whether the light is to be turned on or off, based on the condition of the leading vehicle.
When the leading vehicle is turning right or left at a crossing, the following vehicles turn on their headlights before turning right or left, or just when the leading starts turning right or left. Pedestrians and drivers in oncoming vehicles can find the line of the vehicles in the crossing at the appropriate timing.
In a twelfth aspect of the present invention, the following vehicle further comprises an on-state maintaining device (steps 161 to 167 in the ninth embodiment) for keeping the light on after the turning on of the light until a predetermined time has passed or until the following vehicle travels a predetermined distance.
The on-state maintaining device keeps the light on until a predetermined time has passed or until the following vehicle travels a predetermined distance. Even when the signal for tuning on or off the light is received, the light is not turned on or off, and is kept on. Thus, the frequency of turning on or off the light is reduced, and the lives of the lights can be lengthened.